Construction column



March 13, 1934. w. A. KRANER CONSTRUCTION COLUMN Filed April 22, 1932 INVENTOR. Wye/22w H. (24/152 BY /M%%. [a ATTORNEYS. J

Patented Mar. 13, 1934 CONSTRUCTION COLUMN Warren A. Kraner,

San Francisco, Calif., assignor to Cement Wrapped Pipe Company, Ltd, San

Francisco, Calif a corporation of Arizona Application April 22, 1932, Serial No. 606,893 4 Claims. (01. 61-54) This invention relates generally to the construction of columns, particularly those employed in piers or abutments, which are commonly known as piles.

It is a general object of the invention to devise a column of the type having a concrete jacket, in which the jacket will be so securely locked to the core of the column that the column can be driven into a formation without disrupting the jacket, or without loosening the jacket with respect to the core.

It is a further object of the invention to devise a column or pile which will not only be successful in practical application, but which can also be readily manufactured at a minimum of cost.

Further objects of the invention will appear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawing. It is to be understood that the appended claims are to be accorded a range of equivalents consistent with the state of the prior art.

Referring to the drawing:

Fig. 1 is a side elevational view in transverse cross section, illustrating a column incorporating the present invention.

Fig. 2 is a side elevational view of a column, constructed as illustrated in Fig. 1, after being driven into an underlying formation to form a pile for a pier.

In the past it has been proposed to coat wooden piles with concrete in order strength and protection against certain destructive marine pests. Such coatings have not been widely used because of certain inherent disadvantages. In the past it has been relatively diffioult and expensive to manufacture such concrete coated or jacketed piles, due to the methods employed in applying the concrete. However, aside from the cost of manufacture, it has been difficult if not impossible to drive such prior jacketed piles into an underlying formation, without disrupting the bond between the concrete and the wooden core, or without causing breakage of the concrete jacket. If the concrete jacket becomes loosened, water is permitted to seep between the jacket and the core, and the core will be subjected to destruction by marine pests, substantially the same as if the concrete jacket did not exist.

In the invention described herein, the concrete jacket is applied according to the method disclosed in my co-pending application Serial Number 537,009, filed May 13, 1931, thus enabling manufacture on a commercial basis at a relatively low cost, and the concrete is securely anchored o the outer peripheral surface of the wooden core to prevent loosening or slippage of the jacket with respect to the core, when the pile is being driven into an underlying formation.

That form of the invention illustrated in the drawing consists of a solid wooden core 10, genrally cylindrical in form, which has applied thereto an outer concrete jacket 11. Jacket 11 is provided with an imbe-clded foraminous metal re- 65 inforcement 12. To provide adequate anchorage between the concrete jacket and the core 10, the periphery of the core is shown provided with a spiral groove 13, which is cut into the periphery of the core before the concrete is applied. An integral spiral rib 14, formed on the inner surface of jacket 11, is interlocked within groove 13. Interposed between the concrete jacket and the outer surface of core 10, I preferably provide a coating 16 of water impervious material, as for example one having a base of asphalt.

A complete pile constructed in accordance with my invention is shown in Fig. 2. The lower end portion 17 of the core is not covered with concrete, and is driven into the hard underlying v30 strata 18. The lower end portion 19 of the concrete jacket extends to a point substantially below the upper surface of the mud strata 21. In driving such a pile in position, the upper end is repeatedly struck heavy blows with a ram, and 35 because of the inertia or weight of the concrete jacket, the jacket tends to break loose from the core, and permit relative slippage. With my construction the jacket is so securely anchored to the core, that such loosening of the jacket and the relative slippage cannot take place.

In manufacturing my pile, the first step is to cut suitable indentations into the outer periphcry of the wooden core, to afford an interlock with the concrete jacket to be subsequently applied, as for example by cutting the spiral groove illustrated. The outer surface of the core 10 is coated with a suitable water proofing composition, as for example one having a base of asphalt as has been previously mentioned. The concrete jacket is then applied, preferably according to the meth- 0d disclosed in my co-pending application Serial Number 537,009. The concrete must be so applied as to fill in the groove 13, or if desired, the groove can be filled in with plastic concrete before the outer or main portion of the jacket is applied, in which event the two applications of concrete become bonded together. Without reviewing in detail the method of said co-pending application Serial Number 537,009, it may be briefiy stated that it involves wrapping a ribbon or strip of plastic concrete upon the core spirally, together with a strip of embedded foraminous reinforcement. The reinforcement as it is applied to the core is maintained under tension, so that after the concrete sets, it is held tightly upon the core. The thickness of the concrete jacket may vary according to requirements and this variation can be made either by varying the thickness of the concrete layer being applied, or by making a plurality of applications, one on top of the other.

I claim:

1. In a column, an elongated core having its outer periphery spirally grooved, and a jacket of reinforced concrete surrounding the core, portions of said jacket filling the grooves in the outer periphery of the core to form an interlock.

2. In a column, an elongated core having a spirally grooved outer periphery, a jacket of reinforced concrete surrounding the core, portions of said jacket filling the grooves to effect an interlock, and a Waterproof coating interposed be tween the jacket and the core.

3. In a column, an elongated core having a grooved outer periphery, the grooves continuing entirely about the core, and a jacket of reinforced concrete surrounding the core, portions of said jacket filling the grooves in the outer periphery of the core to form an interlock.

4. In a column, an elongated core having a grooved outer periphery, the grooves continuing entirely about the core and presenting substantially right angled end shoulders, and a jacket of reinforced concrete surrounding the core, portions of said jacket filling the grooves in the outer periphery of the core to form an interlock.

WARREN A. KRANER. 

